The present invention relates to detergent compositions comprising a mannanase, a bleach system comprising one or more of the following components: a source of hydrogen peroxide and a hydrophobic bleach activator.
Performance of a detergent product is judged by a number of factors, including the ability to remove soils, and the ability to prevent the redeposition of the soils, or the breakdown products of the soils on the articles in the wash. Therefore, detergent compositions include nowadays a complex combination of active ingredients which fulfil certain specific needs. In particular, current detergent formulations generally include surfactants, bleaching agents and detergent enzymes.
Indeed, bleaching systems comprising an hydrophobic bleach activator and a source of hydrogen peroxide are known in the art to provide significant whitening, cleaning and greasy stain removal benefits such as on cosmetic and food greasy stains.
Perborate is well-known in the art as a laundry or dish additive that provide available oxygen via a hydrogen peroxide release mechanism. Perborate is broadly used in laundry or dish detergent due to its high performance and its attractive cost.
However it has been recognised in the art that the side product formed during the release of hydrogen peroxide from perborate, i.e. meta borate derivatives, complex with sugar polymers such as starch and leads to cleaning negative (EP-A-736 085). It has been surprisingly found that mannose polymers such as guar gum also cross-link with perborate thereby rendering the food or cosmetic stains even harder to remove by perborate-containing detergents. It has additionally been surprisingly found that the borate cross-linking with guar gum reduces the activity of the enzyme on such gum/borate complex substrates.
Food and cosmetic stains/soils represent the majority of consumer relevant stains/soils and often comprise food additives such as thickener/stabiliser agents. Indeed, hydrocolloids gums and emulsifiers are commonly used food additives. The term xe2x80x9cgumxe2x80x9d denotes a group of industrially useful polysaccharides (long chain polymer) or their derivatives that hydrate in hot or cold water to from viscous solutions, dispersions or gels. Gums are classified as natural and modified. Natural gums include seaweed extracts, plant extrudates, gums from seed or root, and gums obtained by microbial fermentation. Modified (semisynthetic) gums include cellulose and starch derivatives and certain synthetic gums such as low methoxyl pectin, propylene glycol alginate, and carboxymethyl and hydropropyl guar gum (Gums in Encyclopedia Chemical Technology 4th Ed. Vol. 12, pp 842-862, J. Baird, Kelco division of Merck). See also Carbohydrate Chemistry for Food Scientists (Eagan Press-1997) by R. L. Whistler and J. N. BeMiller, Chap 4, pp 63-89 and Direct Food Additives in Fruit Processing by P. Laslo, Bioprinciples and Applications, Vol 1, Chapter II, pp313-325 (1996) Technomie publishing. Some of these gums such as guar gum (E412), locust bean (E410) are widely used alone or in combinations in many food applications (Gums in ECT 4th Ed., Vol. 12 pp 842-862, J. Baird, Kelco division of Merck).
The guar gum used in these food and cosmetic stains is obtained from the seed endosperm of the leguminous plant Cyamopsis tetragonoloba. The guar gum (also called guaran) extracted from the dicotyledonous seed is composed of a 1-4, b-D-mannopyranosyl unit backbone and is used as a thickening agent in dressing and frozen products and cosmetics (H. -D. Belitz, Food Chemistry pp 243, English version of the second edition, Springer-verlag, 1987, ISBN 0-387-15043-9 (US)) and (Carbohydrate Chemistry for Food Scientists, R. L. Wilstler, eagan press, 1997, ISBN 0-913250-92-9) and (Industrial Gum, second editions, R. L. Whistler pp 308, Academic Press, 1973, ISBN, 0-12-74-6252-x). The locus bean gum (also called carob bean gum or St Jon""s bread) is also used in the food industry and is extracted from the seed of an evergreen cultivated in the Mediterranean area. The locus bean gum probably differs from the structure of guar gum only in smaller number of D-galactosyl side chains and have the same 1-4, b-D-mannopyranosyl backbone. In leguminous seeds, water-soluble galactomanann is the main storage carbohydrate, comprising up to 20% of the total dry weight in some cases. Galactomannan has a xcex1-galactose linked to O-6 of mannose residues and it can also be acetylated to various degree on O-2 and O-3 of the mannose residues.
It is known that these hydrocolloid gums have a very high affinity for cellulose materials and are hard to remove, even with modem bleaching agents.
As described above, there is a continuous need to formulate detergent compositions which provide superior cleaning performance, especially on cosmetic and food stains, and superior whiteness performance. This objective has been met by formulating detergent compositions comprising a mannanase and a bleaching system preferably comprising a hydrophobic bleach activator and a source of hydrogen peroxide.
Additionally, the action of percarbonate on bleacheable stains is broadly known in the art. The active ingredient released from percarbonate, i.e. H2O2, is identical to the active ingredient released from perborate, but without the release of borate material. It has now been surprisingly discovered that the combined use of percarbonate and mannanase, especially at specific levels, provides a synergetic removal of difficult stains such as food and cosmetic stains comprising mannans, in particular at low temperatures.
It has further been found that the ternary system consisting of percarbonate/mannanase/protease at specific levels provides an even better result on said stains.
It has been surprisingly found that such compositions provide superior cleaning and whitening due to the synergistic effect of hydrophobic bleach activator bleaching system providing significant cleaning and removing greasy stains and the mannanase enzyme degrading residual hydrocolloid gums. This bleachxe2x80x94enzyme mixed system delivers an outstanding cleaning and whitening effect, especially on these cosmetic and food stains.
It has been further found that the performance of the detergent compositions of the present invention is enhanced by the addition of a cationic surfactant, a chelant and/or mixtures thereof.
Mannanases have been identified in several Bacillus organisms. For example, Talbot et al., Appl. Environ. Microbiol., vol. 56, No. 11, pp. 3505-3510 (1990) describes a xcex2-mannanase derived from Bacillus stearothermophilus in dimer form having a MW of 162 kDa and an optimum pH of 5.5-7.5. Mendoza et al., World J. Micobio. Boitech., vol. 10, no. 5, pp. 551-555 (1994) describes a xcex2-mannanase derived from Bacillus subtilisis having a MW of 38 kDa, an optimum activity at pH 5.0/55xc2x0 C. and a pI of 4.8. J0304706 discloses a xcex2-mannanase derived from Bacillus sp. having a MW of 37+/xe2x88x92 3 kDa measured by gel filtration, an optimum pH of 8-10 and a pI of 5.3-5.4. J63056289 describes the production of an alkaline, thermostable xcex2-mannase, which hydrolyses xcex2-1,4-D-mannopyranoside bonds of e.g. mannans and produces manno:oligo:saccharides. J63036774 relates to a Bacillus micro-organism FERM P-8856 which produces xcex2-mannanase and xcex2-mannosidase, at an alkaline pH. A purified mannanase from Bacillus amyloliquefaciens and its method of preparation useful in the bleaching of pulp and paper, is disclosed in WO97/11164. WO91/18974 describes an hemicellulase such as a glucanase, xylanase or mannanase, active at extreme pH and temperature and the production thereof. WO94/25576 describes an enzyme exhibiting a mannanase activity derived from Aspergillus aculeatus CBS 101.43, that might be used for various purposes for which degradation or modification of plant or algae cell wall material is desired. WO93/24622 discloses a mannanase isolated from Trichoderma reesie for bleaching lignocellulosic pulps.
However, the synergistic combination of a mannanase and a bleach system for superior whitening, stain removal, dingy cleaning and/or superior cleaning performance in a detergent composition, has never been previously recognised.
The present invention relates to detergent compositions comprising a mannanase and a bleach system, preferably a source of hydrogen peroxide, more preferably percarbonate, and optionally, but preferably, a hydrophobic bleach activator. These compositions provide superior cleaning performance, stain removal, especially on cosmetic and food stains, especially mannans-containing cosmetic and/or food stains, dingy cleaning and/or superior whiteness performance.